They're the 2 peice ones with a nickel alloy case walls and a thick aluminum webbing. I found a thousand new unprimed shellahock cases at a show for about the same price as 1x fired, mixed head stamp, still has the spent primer range trash, I guess because no one knows what they are. They're supposed to be pretty tough. I was looking for something "distinctive" to run my illogically hot subgun loads in. I would say these are pretty distinctive.